Researchers of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington found that funding for health in developing countries has quadrupled over the past two decades – from $5.6 billion in 1990 to $21.8 billion in 2007. Private donors are shifting the paradigm for global health aid away from governments and agencies like the World Bank and the United Nations and making up an increasingly large piece of the health assistance pie – 30% in 2007. However, health aid does not always reach either the poorest or unhealthiest countries.

Overall, poor countries receive more money than countries with more resources, but there are strong anomalies. The study for example brought to light that two of the world's emerging economic super powers, China and India, receive huge amounts of health aid. Or that Mali and Colombia have about the same level of sickness, but Colombia receives three times as much health funding.

"We don't know exactly why some countries seem to be far outpacing other countries, but historical, economic and political ties appear to be a factor," said Nirmala Ravishankar, an IHME research scientist and the study's lead author. "Some are former colonies of the countries now giving them aid, and, in other cases, health aid seems to coincide with defense spending or drug interdiction efforts. This is an area that begs for more research."

Moreover, where the money is being targeted within those countries also merits more scrutiny. Based on the research for 2007, HIV/AIDS receives at least 23 cents out of every dollar going into development assistance for health. Tuberculosis and malaria received less than a third of that, even though the combined burden for those diseases is greater than that from HIV/AIDS.